benchtests/bench-pthread-lock-base.c

   1 /* Measure lock functions for different threads and critical sections.
   2    Copyright (C) 2022-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #define TEST_MAIN
  20 #define TIMEOUT (20 * 60)
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <math.h>
  27 #include <pthread.h>
  28 #include <sys/time.h>
  29 #include <sys/sysinfo.h>
  30 #include "bench-timing.h"
  31 #include "json-lib.h"
  32
  33 static bench_lock_t lock;
  34 static bench_lock_attr_t attr;
  35 static pthread_barrier_t barrier;
  36
  37 #define START_ITERS 1000
  38
  39 #pragma GCC push_options
  40 #pragma GCC optimize(1)
  41
  42 static int __attribute__ ((noinline)) fibonacci (int i)
  43 {
  44   asm("");
  45   if (i > 2)
  46     return fibonacci (i - 1) + fibonacci (i - 2);
  47   return 10 + i;
  48 }
  49
  50 static void
  51 do_filler (void)
  52 {
  53   char buf1[512], buf2[512];
  54   int f = fibonacci (4);
  55   memcpy (buf1, buf2, f);
  56 }
  57
  58 static void
  59 do_filler_shared (void)
  60 {
  61   static char buf1[512], buf2[512];
  62   int f = fibonacci (4);
  63   memcpy (buf1, buf2, f);
  64 }
  65
  66 #pragma GCC pop_options
  67
  68 #define UNIT_WORK_CRT do_filler_shared ()
  69 #define UNIT_WORK_NON_CRT do_filler ()
  70
  71 static inline void
  72 critical_section (int length)
  73 {
  74   for (int i = length; i >= 0; i--)
  75     UNIT_WORK_CRT;
  76 }
  77
  78 static inline void
  79 non_critical_section (int length)
  80 {
  81   for (int i = length; i >= 0; i--)
  82     UNIT_WORK_NON_CRT;
  83 }
  84
  85 typedef struct Worker_Params
  86 {
  87   long iters;
  88   int crt_len;
  89   int non_crt_len;
  90   timing_t duration;
  91 } Worker_Params;
  92
  93 static void *
  94 worker (void *v)
  95 {
  96   timing_t start, stop;
  97   Worker_Params *p = (Worker_Params *) v;
  98   long iters = p->iters;
  99   int crt_len = p->crt_len;
 100   int non_crt_len = p->non_crt_len;
 101
 102   pthread_barrier_wait (&barrier);
 103   TIMING_NOW (start);
 104   while (iters--)
 105     {
 106       LOCK (&lock);
 107       critical_section (crt_len);
 108       UNLOCK (&lock);
 109       non_critical_section (non_crt_len);
 110     }
 111   TIMING_NOW (stop);
 112
 113   TIMING_DIFF (p->duration, start, stop);
 114   return NULL;
 115 }
 116
 117 static double
 118 do_one_test (int num_threads, int crt_len, int non_crt_len, long iters)
 119 {
 120   int i;
 121   timing_t mean;
 122   Worker_Params *p, params[num_threads];
 123   pthread_t threads[num_threads];
 124
 125   LOCK_INIT (&lock, &attr);
 126   pthread_barrier_init (&barrier, NULL, num_threads);
 127
 128   for (i = 0; i < num_threads; i++)
 129     {
 130       p = &params[i];
 131       p->iters = iters;
 132       p->crt_len = crt_len;
 133       p->non_crt_len = non_crt_len;
 134       pthread_create (&threads[i], NULL, worker, (void *) p);
 135     }
 136   for (i = 0; i < num_threads; i++)
 137     pthread_join (threads[i], NULL);
 138
 139   LOCK_DESTROY (&lock);
 140   pthread_barrier_destroy (&barrier);
 141
 142   mean = 0;
 143   for (i = 0; i < num_threads; i++)
 144     mean += params[i].duration;
 145   mean /= num_threads;
 146   return mean;
 147 }
 148
 149 #define RUN_COUNT 10
 150 #define MIN_TEST_SEC 0.01
 151
 152 static void
 153 do_bench_one (const char *name, int num_threads, int crt_len, int non_crt_len,
 154               json_ctx_t *js)
 155 {
 156   timing_t cur;
 157   struct timeval ts, te;
 158   double tsd, ted, td;
 159   long iters, iters_limit, total_iters;
 160   timing_t curs[RUN_COUNT + 2];
 161   int i, j;
 162   double mean, stdev;
 163
 164   iters = START_ITERS;
 165   iters_limit = LONG_MAX / 100;
 166
 167   while (1)
 168     {
 169       gettimeofday (&ts, NULL);
 170       cur = do_one_test (num_threads, crt_len, non_crt_len, iters);
 171       gettimeofday (&te, NULL);
 172       /* Make sure the test to run at least MIN_TEST_SEC.  */
 173       tsd = ts.tv_sec + ts.tv_usec / 1000000.0;
 174       ted = te.tv_sec + te.tv_usec / 1000000.0;
 175       td = ted - tsd;
 176       if (td >= MIN_TEST_SEC || iters >= iters_limit)
 177         break;
 178
 179       iters *= 10;
 180     }
 181
 182   curs[0] = cur;
 183   for (i = 1; i < RUN_COUNT + 2; i++)
 184     curs[i] = do_one_test (num_threads, crt_len, non_crt_len, iters);
 185
 186   /* Sort the results so we can discard the fastest and slowest
 187      times as outliers.  */
 188   for (i = 0; i < RUN_COUNT + 1; i++)
 189     for (j = i + 1; j < RUN_COUNT + 2; j++)
 190       if (curs[i] > curs[j])
 191         {
 192           timing_t temp = curs[i];
 193           curs[i] = curs[j];
 194           curs[j] = temp;
 195         }
 196
 197   /* Calculate mean and standard deviation.  */
 198   mean = 0.0;
 199   total_iters = iters * num_threads;
 200   for (i = 1; i < RUN_COUNT + 1; i++)
 201     mean += (double) curs[i] / (double) total_iters;
 202   mean /= RUN_COUNT;
 203
 204   stdev = 0.0;
 205   for (i = 1; i < RUN_COUNT + 1; i++)
 206     {
 207       double s = (double) curs[i] / (double) total_iters - mean;
 208       stdev += s * s;
 209     }
 210   stdev = sqrt (stdev / (RUN_COUNT - 1));
 211
 212   char buf[256];
 213   snprintf (buf, sizeof buf, "%s,non_crt_len=%d,crt_len=%d,threads=%d", name,
 214             non_crt_len, crt_len, num_threads);
 215
 216   json_attr_object_begin (js, buf);
 217
 218   json_attr_double (js, "duration", (double) cur);
 219   json_attr_double (js, "iterations", (double) total_iters);
 220   json_attr_double (js, "mean", mean);
 221   json_attr_double (js, "stdev", stdev);
 222   json_attr_double (js, "min-outlier",
 223                     (double) curs[0] / (double) total_iters);
 224   json_attr_double (js, "min", (double) curs[1] / (double) total_iters);
 225   json_attr_double (js, "max",
 226                     (double) curs[RUN_COUNT] / (double) total_iters);
 227   json_attr_double (js, "max-outlier",
 228                     (double) curs[RUN_COUNT + 1] / (double) total_iters);
 229
 230   json_attr_object_end (js);
 231 }
 232
 233 #define TH_CONF_MAX 10
 234
 235 int
 236 do_bench (void)
 237 {
 238   int rv = 0;
 239   json_ctx_t json_ctx;
 240   int i, j, k;
 241   int th_num, th_conf, nprocs;
 242   int threads[TH_CONF_MAX];
 243   int crt_lens[] = { 0, 1, 2, 4, 8, 16, 32, 64, 128 };
 244   int non_crt_lens[] = { 1, 32, 128 };
 245   char name[128];
 246
 247   json_init (&json_ctx, 2, stdout);
 248   json_attr_object_begin (&json_ctx, TEST_NAME);
 249
 250   /* The thread config begins from 1, and increases by 2x until nprocs.
 251      We also wants to test over-saturation case (1.25*nprocs).  */
 252   nprocs = get_nprocs ();
 253   th_num = 1;
 254   for (th_conf = 0; th_conf < (TH_CONF_MAX - 2) && th_num < nprocs; th_conf++)
 255     {
 256       threads[th_conf] = th_num;
 257       th_num <<= 1;
 258     }
 259   threads[th_conf++] = nprocs;
 260   threads[th_conf++] = nprocs + nprocs / 4;
 261
 262   LOCK_ATTR_INIT (&attr);
 263   snprintf (name, sizeof name, "type=adaptive");
 264
 265   for (k = 0; k < (sizeof (non_crt_lens) / sizeof (int)); k++)
 266     {
 267       int non_crt_len = non_crt_lens[k];
 268       for (j = 0; j < (sizeof (crt_lens) / sizeof (int)); j++)
 269         {
 270           int crt_len = crt_lens[j];
 271           for (i = 0; i < th_conf; i++)
 272             {
 273               th_num = threads[i];
 274               do_bench_one (name, th_num, crt_len, non_crt_len, &json_ctx);
 275             }
 276         }
 277     }
 278
 279   json_attr_object_end (&json_ctx);
 280
 281   return rv;
 282 }
 283
 284 #define TEST_FUNCTION do_bench ()
 285
 286 #include "../test-skeleton.c"